This invention relates in general to certain new and useful improvements in water beds, and more particularly, and water beds which include an air chamber surrounding a water chamber in a water bed mattress.
In recent years, water beds have become quite popular and have received wide commercial acceptance. These water beds are relatively simple structures which include a pair of spaced apart upper and lower plastic sheets surrounded by a continuous peripheral side wall to form an inner water chamber or so-called "bladder". The bladder is generally capable of accepting several hundred gallons of water which enables a normal human body to be supported thereon in such manner that all parts of the body which reside in contact with the mattress are supported by the same pressure. In this way, any excessive pressure is prevented from being exerted on any specific portion of the body. Moreover, water beds have been found to be less expensive than the conventional spring and mattress type bed and even more-so, these beds are more easily transported in the empty condition.
In the standardized form of construction, the water bed which essentially constitutes a water mattress, is surrounded by a frame which may be constructed of wood or other structural materials. This frame is designed to provide supporting characteristics and thereby decrease the curvature of the mattress when a body is supported thereon. In this way, a more normal level sleeping surface is provided. These frames oftentimes include a water tight liner material between the frame and the mattress, which provides additional protection for the mattress to reduce the hazard of mattress puncture or other form of rupture. The liner in this frame not only serves to prevent rupture of the mattress from the rigid support frame, but also inherently creates a safety feature in case of a leak in the water bed mattress. If the mattress material should develop a leak, the liner within the frame could contain the water ejecting from the bladder and thereby prevent serious property damage created by several hundred gallons of water.
While a rigid support frame is desirable in order to provide support for the side wall of the water bed mattress, and to enable the availability of a liner in case of water leakage, the actual rigid frame is contradictory to several advantages and purposes of the water bed mattress. One of the distinct advantages of the water bed mattress is that the mattress can be emptied of water and collapsed and folded into a small compact unit for storage and/or transport.
In order to eliminate the necessity of the rigid supporting frame, there have been several proposals to provide a water bed mattress with a surrounding air bladder. It has been proposed that the air bladder which surrounds the water bladder will provide for retention of the water bladder side wall against outward deflection under the influence of water pressure. Several forms of construction of water beds or water bed mattresses of this type have been proposed and are exemplified by U.S. Pat. No. 3,778,852 and U.S. Pat. No. 3,787,907.
Each of the water beds proposed in the prior art, as exemplified by the abovesaid patents, also suffer several limitations which militate against their use. One of the very important features of a water bed which includes a water bladder surrounded by an air bladder is that the air bladder must be sufficiently strong to withstand the pressure exerted by the water included within the water bladder when the mattress is filled.
Each of the water bed mattresses thus far proposed are constructed of plastic sheet material components. These components are generally sealed together by means of conventional heat seal techniques. Inasmuch as the various mattress components are formed with with mating engagable flanges or flaps these seals almost inevitably become butt seals, even though a lap seal would provide far more strength and durability if constructed properly.
Notwithstanding the above, these commercially available mattresses which include both the water bladder and the air bladder are rather complex in their construction which materially adds to the cost of manufacturers and sales price thereof. As a result thereof, these latter forms of water bed mattresses which include both the water bladder and the air bladder have not received the wide commercial acceptance which would otherwise be forthcoming if they provided the required support and in addition could be manufactured at a relatively low cost.
It is, therefore, the primary object of the present invention to provide a water bed mattress which includes a water bladder surrounded by an air bladder and which does not require the employment of a rigid frame.
It is another object of the present invention to provide a water bed mattress of the type stated which does not require a rigid support frame, but which nevertheless enjoys all of the advantages provided by the employment of a rigid frame surrounding the water bed mattress.
It is also an object of the present invention to provide a water bed mattress of the type stated which avoids the necessity of a rigid frame, and which also provides for water confinement and bladder deformation which normally arise in a absence of a rigid frame.
It is an additional object of the present invention to provide a water bed mattress of the type stated including sections which are lap sealed to each other in order to create the necessary water bed mattress components and which provide increased rigidity and structural use.
It is a further object of the present invention to provide a water bed mattress of the type stated which can be manufactured at a relatively low unit cost and which nevertheless fulfills all of the characteristics of a water bed mattress which requires the employment of a rigid support frame.
It is another salient object of the present invention to provide a method of making water bed mattress which requires a minimum of manual attention and thereby substantially reduces the cost of manufacture of the water bed mattress without sacrificing the desired structural capability.
With the above and other ojbects in view, our invention resides in the novel features of form, construction, arrangement, and in combination of parts presently described and pointed out in the claims.